var fs=require('fs')

fs.readFile('./data/a.txt','utf8',function (err,data) {
    if (err){
        throw err
    }
    console.log(data)
    fs.readFile('./data/b.txt','utf8',function (err,data) {
        if (err){
            throw err
        }
        console.log(data)
        fs.readFile('./data/c.txt','utf8',function (err,data) {
            if (err){
                throw err
            }
            console.log(data)
        })
    })
})




